According to page 11 of The Civil War Handbook by William H. Price, copyright 1961, the basic ration for a Union soldier in 1864 was

20 ounces of beef

18 ounces of flour

2.56 ounces of dry beans

1.6 ounces of green coffee

2.4 ounces of sugar

0.64 ounces of salt

They also were to have recieved smaller amounts of the following, pepper, yeast powder, soap, candles, and vinegar. It does point out that they were forced to forage for food as they rarely recieved their full ration. For Confederate rations, it lists the following for the Army of Northern Virginia in 1863, which is per 100 men for a thirty day period:

1/4 lb. of bacon

18 ounces of flour

10 pounds of rice

a small amount of peas and dried fruit when obtainable

The 1862 Army Officer's Pocket Companion: A Manual for Staff Officers in the Field by William P. Craighill (then a 1st Lt. in the Corps of Engineers), reproduced in 2002 by Stackpole Books gives the following on page 89 for every one hunred rations:

3/4 pound either pork or bacon or 1 1/4 pounds either fresh or salt beef

On the same page it lists changes made August 3 1861 as increases as follows

22 ounces bread or flour or 1 pound hard bread

fresh beef as often as the commanding officer of a detachment or regiment requires, but only when practicable

beans and rice or hominy in place of the salt meats issued within the same amount as the salt meats

1 pound of potatoes per man three times a week if practicable

an equivalent value of some proper food issued when apparently all of the above can not be issued in those portions

tea may be given in place of the coffee ration.

At the bottom of page 89 it says that when on campaign, march, or transport ships the ration of hard bread is a pound. On page 90 it says the ration of water per man is a gallon a day for all purposes.

The Library of Congress Civil War Desk Reference, edited by Margaret E. Wagner, Gary W. Gallagher, and Paul Finkelman, copyright 2002, says on pages 641 and 642 that Confederate General S.D. Ramseur reported soldiers in his brigade recievied an eighth to a fourth of a pound of uncooked meat and 1 1/8 pounds of flour per day in December. In January they apparently got a slight improvement on the meat, rising to a fourth to a half pound of meat but only a pint of cornmeal. This was for the winter of 1863-1864.

Rebel Cornbread and Yankee Coffee: Authentic Civil War Cooking and Camaraderie by Garry Fisher, copyright 2001 lists the following on page 22 as the offical U.S. Army daily ration as of July 1861:

20 ounces of fresh or salt beef or 12 ounces of pork or bacon

18 ounces of flour or soft bread or 12 ounces of hard bread or 20 ounces of corn meal

The desiccated vegetables, incase you don't already know, was a vegetable concentrate composed of finely chopped cabagge, carrots, turnips, onions, beets, and string beans in a dry cake about 2" thick. According to William Davis's The Civil War Cookbook, these cakes were dehydrated vegie cakes. Personally, I perfer what the soldiers called them, "desecrated vegetables" or "baled hay."

I've got a few other sources I can provide info from if you want. Davis's The Civil War Cookbook and The Fighting Men of the Civil War, and the Encyclopedia of the American Civil War: A Political, Social, and Military History all have something on rations. The encyclopedia going from pages 1606-1610 while The Fighting Men of the Civil War also has something on naval rations. I can also check the two Patricia Mitchell books I've got.